运动模体中靶区长度与锥形束CT扫描速度的相关性  

The Correlation Research between the Target Length of Respiratory Phantom and Cone-beam CT Scanning Speed

作　　者：张俊俊[1] 杨振[2] 柏朋刚[3] 王玉[3] 李奇欣[3] 邱小平[1] 吕知平[2] 张子健[2] 陈惠琴[3] 

机构地区：[1]南华大学核科学技术学院,湖南衡阳421001 [2]中南大学湘雅医院,湖南长沙410008 [3]福建省肿瘤医院放疗中心,福建福州350014

出　　处：《中国医学物理学杂志》2015年第2期259-261,共3页Chinese Journal of Medical Physics

基　　金：湖南省科技厅项目(2011SK3220)

摘　　要：目的:研究锥形束CT扫描速度与动态模体中靶区长度的相关性。方法 :选用QUASAR(Modus,Germany)呼吸运动模体,模体内含运动插件,插件中心内嵌入一边长3 cm的立方体,用其来模拟运动靶区。设置模体振幅为0.5、1、2 cm,每一振幅分别设20、15、10次/min三种频率,在每振幅下分别行300°、180°、90°/min运动速度的CBCT扫描。计算CBCT图像靶区长度及靶区长度覆盖率与理论结果比较。结果:振幅为5 mm时,300、180、90°/min扫描时所得不同频率下靶区长度分别为(30.17,30.33,30.5)mm;(31.17,31.83,32)mm;(32.5,33.67,33.67)mm;振幅为10 mm时,300°、180°、90°/min扫描时所得靶区长度分别为(32.67,33.67,35.67)mm;(36,37.5,37.65)mm;(40.17,40.5,41.17)mm;振幅为15 mm时,300°、180°、90°/min扫描时所得靶区长度分别为(39.33,41,41.83)mm;(43,46,46.5)mm;(47.83,48.83,49.17)mm。结论 :CBCT扫描速度、模体振幅以及模体运动频率对靶区长度均有影响。扫描速度越慢,图像所得靶区长度越接近靶区长度真实值,但是各种速度下均小于理论靶区长度。振幅越小时所得靶区长度越接近于靶区理论值,靶区覆盖率越高。临床实践中使用CBCT对动态肿瘤监控时应使用患者平静呼吸的慢速扫描。Objective To study the correlation research between the CBCT scanning speed and the length of the respiratory phan- tom. Methods The QUASAR respiratory phantom was selected to simulate the movement of target volume embedded the move- ment plug-in which contained a 3＊3＊3 cm cubes. Under the situation, we set the phantom movement amplitude to 0.5, 1, 2 cm and the amplitude were 20, 15, 10 times/minute of fi＇equency, respectively. Then under each amplitude, set up 300, 180, 90 degr- ees / minutes of CBCT scanning speed. The length of target obtained by CBCT scanning images was compared with the theoret- ical target length. Results The target length is （30.17, 30.33, 30.5） mm; （31.17, 31.83, 32） mm;（32.5, 33.67, 33.67） mm when its amplitude is 5 mm and the scanning speed is respectively 300°, 180°, 90°/ minutes; the target length is respectively （32.67,33.67,35.67） rnm（36, 37.5, 37.65） mm;（40.17, 40.5, 41.17） mm when its amplitude is 10 mm and scanning speed is respe- ctively 300°, 180°, 90°/min; the target length is respectively（39.33, 41, 41.83） mm（43, 46, 46.5） mm（47.83, 48.83, 49.17） mm when its amplitude is 15 mm and scanning speed is respectively 300°, 180°, 90°/minutes. Conclusion The slower the scanning speed is, the more close to the truth value of the target length it obtained. But the length of target scanned under different speeds are lower than theoretical value. The smaller amplitude leads to the value more close to the target volume the theoretical value and the higher target volume coverage. In clinic, when we monitor dynamic tumor, we require patients staying slow breathing and under slow CBCT scan speed.

关 键 词：锥形束CT 呼吸运动模体 靶区长度 扫描速度 

分 类 号：R73[医药卫生—肿瘤]